I'm on it! You are right, it looks bad, thanks for pointing it out.
The black spots you see are me previously applying the coating you reference to the various electrical grounding screws SMB installed during the build. On my list is gathering up the grounds and running them all to the Blue Sea Systems 2300 bus bar that I have sitting on the workbench waiting for the appropriate time...
Once done I'll be sure to go back and coat everything that's visible from the outside.
Question: Any thoughts on what to use in the holes once I remove the various screws? I'm currently thinking of simply plugging them with SS threaded bolts.
For reference, here is what it looks like from the inside: